Book VI. MARINE PLANTS. 9?5 



depth between, so as to admit of irrigation. The sets are obtained from old plantations, 

 and planted in rows across the beds at six inches' distance every way, in March or April. 

 No produce worth notice is obtained in the first year, but a full crop in the third, and 

 the shoots will continue to produce for five or six years. The spikes of flowers, and in 

 some cases the entire herbage, are cut over in June, as soon as the flowers expand, and 

 carried immediately to the druggist's still. Some growers distil it themselves. 



6183. The common valerian {Valeriana oflicinalis L.) is sometimes cultivated for its 

 roots for the druggists. It is a native plant, and prefers a loamy soil. In Derbyshire 

 the plants, which are either procured from the offsets of former plantations, or from 

 wild plants found in wet places in the neighbouring woods, are planted six inches asunder, 

 in rows twelve inches apart. Soon after it comes up in the spring the tops are cut off, to 

 prevent its running to seed, which would spoil it. At Michaelmas, the leaves are pulled 

 and given to cattle, and the roots dug up carefully, and clean washed ; the remaining top 

 is then cut close off, and the thickest part slit down to facilitate their drying, which is 

 effected on a kiln, after which they must be packed tight, and kept very dry, or they will 

 spoil. The usual produce is about 18 cwt. per acre. This crop receives manure in the 

 winter, and requires a great deal. 



6184. The orchis or salep plant (Orchis mAscula JL.) is a tuberous perennial, which 

 grows plentifully in moist meadows in Gloucestershire, and other parts of the country. 

 It flowers in May and ripens seeds in July. It has been proposed to cultivate it for its 

 tubers to be used as salep ; but the plant is very difficult of propagation from seed, and 

 can hardly be multiplied at all by the root ; and, though it may answer to collect the 

 tubers and prepare them, it is not likely their culture will ever pay. As the plant is very 

 abundant in some situations, it may be useful to know its preparation, which is thus 

 described in Phil. Trans, vol. lix. 



61S5. The bulb is to be washed in water, and the fine brown skin which covers it is to be separated by 

 means of a small brusli, or by dipping the root in hot water, and rubbing it with a coarse linen cloth. 

 When a sufficient number of bulbs are thus cleansed, they are to be spread on a tin j)late, and placed in 

 an oven heated to the usual degree, where they are to remain six or ten minutes, in which time they will 

 have lost their milky whiteness, and acquired a transparency like horn, without any diminution of bulk. 

 Ueing arrived at this state, they are to be removed, in order to dry and harden in the air, which it will 

 require several days to effect ; or, by using a gentle heat, they may be finished in a few hours. By another 

 process, the bulb is boiled in water, freed from the skin, and afterwards suspended in the air to dry ; it thus 

 gains the same appearance as the foreign salep, and does not grow moist or mouldy in wet weather, which 

 those that have been barely dried by heat are liable to do. Reduced into powder, they soften and dissolve 

 in boiling water into a kind of mucilage, which may be diluted for use with a large quantity of water or 

 milk. Thus prepared, they possess very nutritious qualities ; and if not of the very same species as those 

 brought from Turkey and used for making salep, they so nearly resemble them as to be little inferior. In 

 Turkey the different species of the O'rchis are said to be taken indifterently ; but in England, the O'rchis 

 m^scula is the most common. {Gloucestershire Report, 2>11.) 



Chap. IX. 



Marine Plants used in Agriculture. 



6186. All marine plants m.ay be used as manure with great advantage, either in a recent 

 state or mixed with earth. It is used in this way more or less in all agricultural coun- 

 tries bordering on the sea, and in Britain in all those friths and estuaries, where, from the 

 water not being at the maximum of saltness, the plants which grow in it are not suffi- 

 ciently charged with soda to render it worth while to burn them for the sake of the salt. 



6187. The use of sea-weed, as an article from which kelp might be manufactured, seems to have been 

 practically recognised in Scotland about the beginning of the eighteenth century. The great demand for 

 kelp in the manufacture of glass and soap at Newcastle, and of alum at Whitby, seems to have intro- 

 duced the making of this commodity upon the shores of the Forth, so early as about the year 1720. It 

 began to be manufactured in the Orkney Islands in the year 1723, but in the western shires of Scotland 

 the making of kelp was not known for many years after this date. The great progress of the bleaching 

 of linen cloth in Ireland, first gave rise to the manufacture of kelp in that kingdom ; and from Ireland it 

 was transferred to the Hebrides about the middle of the eighteenth century. On the shores of England 

 the kelp plants are not abundant. 



6188. All marine plants may be used for the manufacture of kelp, but the principal 

 species in use on the British shores belong to the Linnean genus J'ucus. J'ucus 

 vesiculosus {fig, 815. a) is considered by kelp-makers as the most productive ; and the 

 kelp obtained is, in general, supposed to be of the best quality. JF'iicus nodosiis (b) is 

 considered to afford a kelp of equal value to that of the above species, though perhaps it 

 is not quite so productive. J^cus serrktus (c), or black- weed, as it is commonly called, 

 is neither so productive as the preceding, nor is the kelp procured from it so va- 

 luable. This weed is seldom employed alone for the manufacture of kelp ; it is in 

 general mixed with some of the other kinds. i^ucus digitatus (Laminaria digitata 

 H. B. 15, 343.) (rf) is said to afford a kelp inferior in quality to that obtained from any 

 of the others ; it forms the principal part of the drift-weed. 



6189. The plants are cut in May, June, and July, and exposed to the air on the ground till nearly dried, 

 care being taken to prevent them, as much as possible, from being exposed to the rain. They are then 



3 P 



